This invention relates to hermetically sealed refrigeration compressors, and more particularly to an oil distribution system for such compressors adapted to conduct heat energy from the cylinder heads within the compressor housings.
In those refrigeration compressors utilizing a piston-cylinder arrangement for compression, the gaseous refrigerant becomes extremely hot upon compression and conducts heat energy to the cylinder and cylinder head, thereby increasing temperatures of the cylinder and cylinder head. These higher temperatures may cause lubricant to boil and lose its lubricating properties, which eventually results in carbon deposits forming on valves, valve seats, leaf plates and the like. The steady accumulation of such deposits will eventually destroy the integrity of the valve arrangement requiring shutdown of the compressor and replacement of the defective parts.
Generally, the cooling of the cylinder head is left to the suction inlet refrigerant that is delivered directly into the compressor housing. Although adequate to acceptably cool the cylinder head, higher compressor efficiencies are obtainable if the cylinder head is cooled even further.
The most relevant prior art of which applicants are aware is U.S. Pat. No. 2,215,645 issued to Money on Aug. 2, 1938. Money has a short tube extending upwardly from the top opening of the oil passage in the crankshaft that serves to spray oil upon the top surfaces of compressor components. To insure that some of the oil will fall upon the outer surfaces of the piston and cylinder to lubricate them, a baffle is connected to the top of the cylinder to deflect some the sprayed oil so that it may drip downwardly onto the outer surfaces of the piston. It appears that the majority of the oil which is sprayed over the baffle impacts the compressor housing to return to the oil sump in the bottom of the compressor. It should be noted that the baffle in the Money patent is disposed on the most axially inwardly portion of the cylinder to insure deflection of oil to lubricate the piston.
The copending application Ser. No. 374,050, now abandoned, of Billy B. Hannibal, a coinventor of the present invention, is of particular relevance regarding the present invention. In the earlier invention of the copending application the applicant has provided for the cooling of oil pumped upwardly through an oil passage in a crankshaft by fitting an elongated, hollow tube into the oil passage. Oil is pumped upwardly through the tube and, by angularly adjusting the tube relative to the crankshaft rotational axis, slung radially outwardly against the side upper surfaces of the compressor housing to cool the oil as it returns to the sump. Although a portion of the slung oil may contact the cylinder and cylinder head, any cooling experienced by those parts is extremely slight and particularly so with reference to the cylinder head, which may receive none of the oil.
Other devices have been used to decrease the extremely high temperatures of the cylinder head, for example, heat radiation fins disposed on the cylinder head, which have been effective in various degrees in lowering the cylinder head temperature. However, further cylinder head temperature reduction is desirable in order to increase compressor efficiency, prevent accumulation of carbon deposits on the valve arrangements, and prolong the life of parts such as bearings, insulation and the like.